#!/usr/bin/env perl

# Copyright (c) 2017 Franco Fichtner <franco@opnsense.org>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.

use strict;
use warnings;
use autodie;

use Cwd;
use File::Find;
use File::Slurp;

my $src = shift || 'src';
my $cwd = getcwd;
my $lic = << 'END_LIC';
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
END_LIC

my %copyrights = ();

sub process_file
{
    my $filename = $File::Find::name;

    return if not -f "$cwd/$filename";

    my @lines = read_file( "$cwd/$filename" );
    my $possibly_bsd;

    for my $line ( @lines ) {
        $possibly_bsd = 1 if $line =~ /Redistribution and use in source and binary forms/i;
        if ( $line =~ /Apache License/i ) {
            $possibly_bsd = 0;
            last;
        }
    }

    return if not $possibly_bsd;

    for my $line ( @lines ) {
        my $copy = $line;
        next if $line !~ s/copyright\s+\(c\)\s+//i;
        $line =~ s/^[."\*\\#\s]+//g;
        $line =~ s/\s+$//g;
        chomp $copy;
        $copy =~ s/^[\*\\#\s]+//g;
        my ( $start, $end ) = ( 0, 9999 );
        if ( $line =~ s/(\d\d\d\d\s*,?-?\s*)// ) {
            $start = $1;
            $start =~ s/[,\s\-]+//g;
        }
        if ( $line =~ s/(\d\d\d\d\s*,?\s+)// ) {
            $end = $1;
            $end =~ s/[,\s]+//g;
        }
        $end = $start if $end == 9999;
        say STDERR "Error in $filename: $copy" if $end == 0;
        if ( exists $copyrights{$line} ) {
            if ( $start > $copyrights{$line}[0] ) {
                $start = $copyrights{$line}[0];
            }
            if ( $copyrights{$line}[1] == 9999 or $end < $copyrights{$line}[1] ) {
                $end = $copyrights{$line}[1];
            }
        }
        $copyrights{$line} = [ $start, $end ];
    }
}

find( \&process_file, $src );

for ( sort keys %copyrights ) {
    my $date = $copyrights{$_}[0];
    next if $date == 0;
    $date = join '-', @{ $copyrights{$_} } if $copyrights{$_}[1] != $date;
    print "Copyright (c) $date $_\n";
}

print $lic;
